Process and product for distributing photographic material by capillary action



Dec. 18, 1962 E. H. LAND 3,069,266

PROCESS AND PRODUCT FOR DISTRIBUTING PHOTOGRAPHIC MATERIAL BY CAPILLARYACTION Filed 001;. 31, 1960 5 Sheets-Sheet 1 FIG. 7

WM FIG. 2

ATTORNEYS Dec. 18, 1962 E. H. LAND 3,069,266 PROCESS AND PRODUCT FORDISTRIBUTING PHOTOGRAPHIC MATERIAL BY CAPILLARY ACTION Filed D st. 31,1960 3 Sheets-Sheet 2 FIG. 4

IN V TOR.

ATTORNEYS 3,069,266 PHOTOGRAPHIC MATERIAL BY CAPILLARY ACTION Dec. 18,1962 E. LAND PROCESS AND PRODUCT FOR DISTRIBUTING Flled Oct 51, 1960 :5heets-Sheet a INV Nrom {M Z. aw

ATTORNEYS United States Patent Q-filice 3,069,266 Patented Dec. 18, 19523,069,266 PROCESS AND PRODUCT FOR DISTRIBUTING PHOTOGRAPHIC MATERIAL BYCAPIL- LARY ACTION Edwin H. Land, Cambridge, Mass., assignor to PolaroidCorporation, Cambridge, Mass a corporation of Delaware Filed Oct. 31,1960, Ser. No. 68,323 16 Claims. (CI. 9648) This invention relates tophotography and more particularly to photographic processes and productswherein a fluid is distributed between a pair of superposed sheets.

This application is a continuation-in-part of my copending applicationSerial No. 560,381, (now abandoned) filed January 20, 1956, forPhotographic Process and Product.

A variety of photographic processes may be effected by spreading a fluidcompositon in a uniformly thin layer between a pair of superposedsheets. For example, a photosensitive stratum supported on one of thesheets may be developed by a processing composition spread between itand another sheet. Here, spreading may be effected after exposure todevelop an existing latent image or before exposure so that the latentimage formed immediately thereafter develops spontaneously.Alternatively, a photosensitive composition may be spread between thesheets in the presence of a developer to provide a stratum which, whenphotoexposed shortly after being formed, received a latent image thatdevelops spontaneously.

Heretofore, it has been the usual practice to spread the fluidcomposition between the sheets by moving the sheets between a pair ofspecially designed pressure-applying members, such as precisely alignedand carefully fabricated rollers, the design of which may be complicatedby the fact that the fiuid composition is usually provided in acontainer located between the sheets. However, for many purposes, theuse of rollers or other types of pressure-applying members may prove toocostly or inconvenient and it is considered advantageous for these andother reasons to omit them from photographic apparatus of the type inwhich they are usually included.

The present invention has, as one of its objects, the provision of novelphotographic processes and products in the form of. photographic filmunits, which make it possible to distribute a fluid composition in auniformly thin layer between a pair of superposed sheets without the aidof pressure-applying means, or the necessity of applying compressivepressure to the sheets.

The present invention finds applicability in a number of photographicprocesses involving formation of latent images in a variety of materialssuch as the noble metal salts, particularly the silver halides, ferricsalts, diazoniurn compounds, and compounds of the type includingdichromated gelatin. It is particularly applicable to proc esses of thesilver transfer-reversal type, and especially a process, for example,wherein a photoexposed silver halide stratum is treated between twosheets by a silver halide developer and a silver halide solvent. Thereagents reduce exposed silver halide to silver and react with unreducedsilver halide to form a soluble silver complex which in turn is reducedto silver in a silver-receptive environment. This silver-receptiveenvironment may be interspersed with the silver halide and the positiveprint so formed may be retained permanently between the sheets, or thesilver-receptive environment may cornprise a stratum on one of thesheets and is separated from the silver halide by stripping the sheetsapart after the positive print has been formed.

Accordingly, other objects of the invention are: to provide aphotographic process whereby an exposed photosensitive stratum isprocessed by a fluid composition distributed between a pair ofsuperposed sheets by capillary action; to provide a photographic productin the form of a film unit comprising a pair of rigid or rigidlysupported sheets superposed and fixedly spaced at predetermined distanceapart whereby a process of the aforementioned type may be effected; toprovide a photographic product of the aforementioned ty-pe comprising apair of sheets superposed With their inner surfaces so disposed that afluid supplied to one edge of the sheets is caused to be drawntherebetween by capillary action, and means associated with one edge ofthe superposed sheets providing a chamber communicating with the spacebetween said sheets; and the process employing said product to produce avisible photographic image including the step of releasing a fluidcomposition within said chamber so that it is drawn between said sheetsby capillary action.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comp-rises the several steps and the relationand order of one or more of such steps with respect to each of theothers, and the product possessing the features, properties and therelation of elements which are exemplified in the following detaileddisclosure, and the scope of the application of which will be indicatedin the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings wherein:

FIGURE 1 is an exaggerated cross-sectional view of one form of thephotographic product of the invention for eifecting the processingthereof;

FIG. 2 is a cross-sectional view taken along the line 22 of FIG. 1;

FIG. 3 is a cross-sectional view taken along the line 3--3 of FIG. 1;

FIG. 4 is a diagrammatic perspective view, partially in section, of acamera with which the product of FIG. 1 is adapted to be employed foreffecting the process of the present invention;

FIG. 5 is an exaggerated sectional view, similar to FIG. 1, of anotherembodiment of the product of the invention;

FIG. 6 is a view, similar to FIG. 5, of another embodiment of theinvention;

FIG. 7 is an exaggerated cross-sectional view taken substantially alongthe line 7-7 of FIG. 6;

FIG. 8 is a view, similar to FIG. 6, of another form of the invention;

FIG. 9 is a diagrammatic perspective view, partially in section,illustrating typical apparatu for effecting the processing of the filmunits of FIGS. 6 through 8; and

FIGS. 10 and 11 are exaggerated cross-sectional views of still anotherembodiment of the film unit of the invention illustrating the method ofemploying said film unit.

Generally, each of the film units hereinafter specifically describedcomprises two rigid or rigidly supported sheets, at least one of whichis transparent. The two sheets, during fabrication, are superposed withtheir inner surfaces parallel and close together, the spacing betweenthe inner surfaces of the sheets benig such that a fluid supplied to thespace between the sheets at one edge thereof will be rapidly drawnbetween the sheets by capillary action without further manipulation ofthe sheets. While the film units described may be useful to effect avariety of processes, each film unit, together with the fluid spreadbetween the sheets, is described as preferably including the materialsnecessary for producing a positive photographic print by silver transferreversal. When such a film unit is in operation, the silver halidecomposition is subjected between the sheets to a silver halide developerand a silver halide solvent and in practice one or more of thesematerials are made available at any of a variety of locations in thefilm unit, for example dispersed in a dry condition on one or both ofthe sheets. The arrangement is such that the developer and solvent donot act upon the silver halide composition until an aqueous fluid, whichmay or may not contain one or more of these materials, is spread betweenthe sheets. Each film unit includes means associated with one edge ofthe sheets providing a chamber communicating with the space between saidsheets. The aqueous fluid may be supplied within the chamber so that itcan be released therein for spreading between the sheets or from anexternal source, in which case means are pro- 'vided in the apparatuswith which the film unit is employed for introducing the fluid into thechamber.

Following formation of the positive print, the two sheets may beseparated from one another, one of the sheets then serving as a supportfor the print; or the sheets may be retained in superpositionpermanently so that they form a protective barrier against harm to ordefacement of the print. Photographic processes and film units of thetype wherein a pair of rigid sheets, between which a positive print isformed, are maintained in permanent superposition are described andshown in my copending application Serial No. 523,885 (now Patent No.2,982,650, issued May 21, 1961), filed July 22, 1955.

The typical film unit may be so constituted that a photosensitive silverhalide stratum is carried on one of the sheets, a silver-receptivestratum is carried on the other and the fluid includes an aqueousalkaline solution of a silver halide developer and a silver halidesolvent. This fluid may be released for distribution between the sheetseither after exposure of the silver halide stratum or immediately beforeexposure so that the latent image formed in the silver halide stratum isdeveloped and a positive print is formed spontaneously. Any of thesilver halide developer and silver halide solvent, and even the alkali,which are to effect silver transfer reversal may be carried in drycondition on either or both sheets or in the solution to be spreadbetween the sheets. Alternatively, the fluid may comprise aphotosensitive composition to be distributed between the sheets in thepresence of a developer to provide a stratum which, when photoexposedshortly following its formation, receives a latent image that developsspontaneously. In this form of film unit, the developer may be carriedin many ways, for example dispersed in dry condition on one of thesheets. This film unit requires no shielding from environmental lightuntil the photosensitive composition is distributed between the sheets,and this may be effected within the exposure chamber of a camera wherethe photosensitive composition forms a photosensitive stratum which,when photoexposed through one of the sheets, receives a latent imagefrom which a useful print is formed without further manipulation ortreatment.

The two sheets comprising the film unit are positioned duringfabrication with their inner surfaces parallel and spaced apredetermined distance apart. The spacing between the sheets isrelatively small, ranging, for example, between twoand six-thousandthsof an inch, so that a liquid introduced into or supplied to the spacealong one margin thereof is drawn between the sheets by capillaryaction. A nonviscous, aqueous liquid comprising any of theabove-mentioned materials and reagents is ideally suited for spreadingbetween the sheets by capillary action, particularly if the liquidcontains inorganic salts such as sodium hydroxide which have a strongtendency to increase the surface tension of the liquid and therebyincrease the area over which the liquid will spread by capil laryaction, and the rapidity at which the spreading occurs. The area andrapidity of spread of the liquid, due to capillary action, may beadditionally increased by providing in the liquid a surface-active agentof the type which decreases the angle of contact of the liquid with theinner surfaces of the two sheets.

One or both of the rigid sheets are transparent, depending on whetherthe two sheets are to be separated or are to remain in superpositionfollowing production of a photographic print, and if the sheets areretained in superposition, whether the print produced between the sheetsis to be viewed by reflected or transmitted light. Suitable materialsfor this purpose are glass and glasslike organic polymers which areoptically clear and water insoluble. Examples of suitable glasslikeorganic polymers are acrylates, styrenes, cellulosics, vinyl chloridecopolymers, and condensation polymers. These sheets should have asufliciently high modulus of fiexure to resist deformation and sheetscomposed of such glass and glasslike materials have been found to besufficiently rigid when as little as one-hundredth of an inch thick. Forgood optical clarity, it is preferred that these sheets be no more thantwothousandths of an inch thick.

Reference is now made to FIGS. 1 through 3 wherein there is illustratedone form of film unit embodying the present invention. This film unit,generally designated at 19, comprises a pair of rigid sheets 12 and 14mounted in superposed relation. The two sheets are retained together bya suitably formed frame completely surrounding the sheets as describedin my above-mentioned application, or, as in the form shown, by a pairof retaining elements 16 and 18. Still another means for holding the twosheets together at either or both ends thereof may comprise a notch anda catch adapted to be engaged in the notch, formed as an integral partof the end section or sections of the two sheets. Sheet 12 is shown assupporting a stratum 20 which in one form contains a photosensitivesilver halide, and sheet 14 is shown as supporting a stratum 22 which inone form contains silver precipitating nuclei. Retaining elements 16 and18 are generally channel-shaped in cross section and are secured aroundopposite end edge sections of the sheets. The retaining elements may beprovided with reentrant side wall sections 24 adapted to engagecorresponding raised shoulders or ridges 26 on the outer surfaces of thesheets adjacent their ends so as to retain element 16 in engagement withthe sheets. Suitable materials for the retaining elements are preferablymaterials such as organic plastics and rubber which can be readilyformed by molding and are substantially rigid so as to retain the sheetstogether, yet sufliciently deformable to permit the retaining elementsto be engaged with or disengaged from the sheets. Sheets 12 and 14 arespaced apart by such means as spacer strips 28 secured between thelongitudinal edges of the sheets. Spacer strips 28 may be formed of anysuitable material, preferably one which is incompressible, and may beformed, for example, of an adhesive material which serves to secure thesheets together as well as to predeterminedly space them apart.

Retaining element 18 is substantially equal in length to the width ofsheets 12 and 14 and is open at both ends. This retaining element is soformed as to provide, when coupled with a pair of sheets at one endthereof, a passage 30 extending from end to end of the retaining elementand communicating with the space between the sheets. This passage allowsfor the escape of air from between the sheets as a fiuid is spreadtherebetween, commencing at the opposite edge, as well as providing areservoir for collecting excess liquid.

Retaining element 16 is substantially longer than the width of thesheets and includes end sections 32 and 34 which extend around thelateral edges of the sheets. Retaining element 16 is so formed as toprovide an elongated rounded chambcr 36 at least equal in length to thewidth of the sheets and communicating with the space between the sheets.Mounted within chamber 36 is an elongated container 38 carrying anaqueous fluid indicated at 40 which, in one form, comprises an aqueousalkaline solution, a silver halide developer and a silver halidesolvent. Fluid t) is provided in an amount at least sufiicient tocompletely fill the space between the sheets when spread by capillaryaction substantially from end to end thereof.

Container 33 is of the type disclosed in my copendin application SerialNo. 820,266, filed June 15, 1959 and, in the form shown, is generallycylindrical and extends completely from end to end of chamber 36. Thewall of container 38 is preferably thin and flexible and is formed of amaterial which is impervious to fluid 40 and preferably impervious toair and water vapor. Container 38 is secured at one end in a roundopening in end section 32, a plug 42 being provided for closing theopening in the end section as Well as for closing the end of thecontainer. The other end of container 38 extends through a taperedpassage 44 in end section 34. Passage 44 converges to a widthsubstantially equal to twice the thickness of the material comprisingthe wall ofcontainer 38 so that the end of the container extendingthrough the passage is retained in a closed position. An end portion 46of the container extends beyond end section 34 Whereby the container maybe manually grasped, the container being adapted to be withdrawn fromchamber 36 in the direction of its elongation through passage 44. Theinner facing surfaces of the wall of the container in the region of endportion 46 may be secured or bonded together to assure sealing of thecontainer. As the container is withdrawn, plug 42 remains secured in endsection 32, leaving the end of the container open and the sides ofpassage 44 act to progressively compress the container, causing itsfluid contents to be released Within chamber 36 for distribution betweenthe sheets.

Before or immediately following spreading of fluid 40 from chamber 36between sheets 12 and 14, stratum 20, which as stated above in one formcontains silver halide, is photoexposed to produce therein a latentimage. Fluid 40, as stated above in one form, contains a developer whichreduces exposed silver halide in stratum to silver, and a silver halidesolvent which reacts with unreduced silver halide to form a complexsilver salt that diffuses to stratum 22 where, in the presence ofunexhausted silver halide developer and a silver precipitating agent, itis reduced to silver. The period initiated by spreading fluid andterminated by completing negative formation in stratum 2i) and positiveformation in stratum 22 ordinarily ranges from 40 to 120 seconds induration. The two sheets 12 and 14 supporting, respectively, strata 20and 22, may then be stripped apart or the sheets may be allowed toremain in superposition, as described in my aforementioned applicationSerial No. 523,885, with the solution thereafter dried to form a more orless solid residue which may serve as an adhesive to at least aid inholding the sheets together.

In embodiments of the film unit employing a gelatino silver halideemulsion, it may be desirable to coat or otherwise treat the gelatin inorder to inhibit or delay the absorption of water of the processingfluid by the gelatin; yet such treatment should be of the characterwhich does not interfere with image formation and transfer. The gelatinis subjected to this treatment in order units according to the inventionand useful in the method thereof. By way of example, the receivingsheets employed for this purposewere prepared according to the methoddescribed in copending application Serial No. 48,327, filed in the namesof Edwin H. Land and Meroe M. Morse on August 8, 1960, and consisted ofa dispersion of silver precipitating nuclei in the form of goldcondensed from the vapor phase onto the surface of a rigid glass plate.Film units were produced by securing a glass lantern slide plate,treated in the manner described, in face to face relation with a glassimage-receiving sheet, prepared as described, at the margins of thesheets with a gap between the sheets having a depth ranging between.0025 and .0035 inch, the gap being maintained by spacing elementslocated between the facing surfaces of the glass plates.

Film units prepared in this manner were exposed to actinic light andtreated by immersion of an edge of the plates in a nonviscous processingfluid prepared in the manner described in US. Patent No. 2,662,822,issued December 5, 1953, in the name of Edwin H. Land and comprising:

Water cc 1860 Sodium sulfite grams 119 Sodium hydroxide do 74. 6 Sodiumthiosulfate do 14.5 Toluhydroquinone do 52 The processing liquid wasdrawn into the interspace between the glass plates of the film unit bycapillary action to cover the area of the plates exposed and produced atransfer image therein.

Reference is now made to FIG. 4 of the drawings wherein there isillustrated photographic apparatus in the form of a camera 48 with whichthe film unit of the invention is adapted to be employed for producing aphotographic print. The camera comprises a housing having a rear section50 and a tapered forward section or bellows 52 mounting a conventionallens and shutter assembly 54. In one side of the camera housing there isprovided a passage 56 having a narrow elongated intermediate section 58adapted to slidably receive the pair of superposed sheets comprising afilm unit and upper and lower enlarged end sections and 61, re-

- spectively, adapted to receive retaining elements 16 and 18 located atthe ends of the film unit. The focal surto prevent the gelatin fromswelling so rapidly as to close the capillary interspace before theprocessing liquid has had an opportunity to spread over the desiredarea. As an example of a photosensitive element useful in the inventionand comprising a gelatino silver halide emulsion treated to inhibitswelling, glass lantern slide plates, manufactured by Eastman KodakCompany, were treated with a solution of tetra isopropyl titanate inhexane. The solution was prepared consisting of 1 to 2 percent byvolume. of tetra isopropyl titanate in hexane, and the treatmentconsisted of flowing the solution on the emulsion surface, draining theexcess, repeating the process after about five minutes drying time, andthen allowing the slide-to dry over night under room conditions beforeuse.

Lantern slide plates treated in this manner were assembled with rigidimage-receiving" sheets to form film face of the lens of assembly 54 islocated within intermediate section 58 of the passage so that thephotosensitive stratum of a film unit located within passage 56 ispositioned for exposure. The camera housing includes a passage 62providing an optical path between the lens and intermediate section 58of passage 56.

Camera 48 is employed in conjunction 'with a film unit 18 by introducingthe film unit into passage 56, commencing at one longitudinal edge ofthe film unit adjacent end section 32 of retaining element 16, andmoving the film unit into exposure position with sheets 12 and 14completely within passage 56 and with end section 34 of retainingelement 16 and end portion 46 of container 38 extending from upperenlarged section 60 of passage 56. A suitable retaining element and/orclosure may be provided on the side of rear housing section 59 adjacentpassage 56 for releasably retaining a film unit within the passage and/or for light-sealing at least intermediate section 58 of the passage.The fluid contents of container 38 may be released within chamber 36 forspreading between the sheets by grasping the container at end portion 46and withdrawing it from the chamber through tapered passage 44.Spreading of the fluid contents of the container is effected with thefilm unit in exposure position either immediately before exposure ismade or following exposure. The film unit is then allowed to remainwithin the camera during a predetermined processing period at the end ofwhich it may be removed from the camera. It is apparent from this 4description of the operation of the camera that the latter can be verysimple and inexpensive to fabricate since all the materials andmechanism necessary to process the film unit are, included in the filmunit itself, the camera merely providing exposure means and a chamber inwhich the film unit is positioned during exposure and processing.

Film unit 10 is positioned for spreading of the fluid preferably withchamber 36 and container 38 disposed with their common axis in asubstantially horizontal plane, that is, with the transverse edges ofthe sheets disposed horizontally so that the fluid contents of thecontainer are more or less evenly distributed throughout the length ofthe chamber (and the width of the space between the sheets) when thefluid is released; and with sheets 12 and 14 extending downward ingenerally vertical planes so that substantially all the fluid releasedwithin chamber 36 is made available for spreading in the space betweenthe sheets. The sheets are positioned sufficiently close together sothat normally there is no tendency for the fluid to flow between thesheets under the influence of gravity. By virtue of this arrangementcapillary action is effective both to spread the fluid (downward)between the Sheets and to prevent the fluid from flowing (downward) frombetween the sheets under the influence of gravity when the supply offluid in chamber 36 is exhausted.

In the forms of film unit wherein one of the sheets carries aphotosensitive stratum, means must be provided for preventing exposureof the photosensitive material by environmental light prior tophotoexposure within the camera. Where the two sheets are to be strippedapart or retained together and the image viewed by reflected light, oneof the sheets may be formed of an opaque material or with an opaquecoating and a suitable opaque cover sheet may be provided for the othertransparent sheet. This cover sheet (not shown) may be so formed that itcan be separated from the transparent sheet of the film unit within thecamera and removed therefrom to permit photoexposure through thetransparent sheet.

Another form of film unit embodying the invention is illustrated in FIG.and is designated at 64. Film unit 64 is similar in most respects tofilm unit and includes a pair of rigid sheets 66 and 68 supporting,respectively, strata 70 and 72 and a retaining element 74 secured aroundthe end edges of the sheets and retained in engagement with the sheetsby reent-rant sections 76 engaged with raised ridges 78 on the endsections of the sheets. Retaining element 74 provides an elongatedrounded chamber 80 extending at least from side to side of the sheetsand communicating with the space between the sheets through a narrowpassage 82, also extending substantially from side to side of thesheets. Chamber 80 contains sufficient processing fluid, indicated at84, to at least completely fill the space between the sheets when spreadtherebetween by capillary action. Fu-id 84 is prevented from being drawnbetween the sheets by an elongated closure element 86 positioned inclosing relation within passage 82-. The closure element may be of anyconvenient cross-sectional configuration and, in the form shown, is anequi-lateral parallelogram. Closure element 86 and retaining element 74are so constructed that one end of the closure element extends throughan opening in the end of the retaining element whereby the closureelement may be grasped and withdrawn in the direction of its elongationfrom passage 82, releasing fluid 84 for spreading between the sheets.

Another form of film unit embodying the invent-ion is indicated at 88 inFIGS. 6 and 7 and is shown together with means for introducing andreleasing a quantity of processing fluid within a chamber communicatingwith the space between the superposed sheets. Film unit 88 includes apair of rigid sheets 90 and 92 secured in facing relation at one end bya retaining element 94 and separated a predetermined distance apart by apair of spacing strips 96 located between the longitudinal margins ofthe sheets. Retaining element 94 includes end walls 98 and 100 and is soformed as to define an elongated rounded chamber 102 at least equal inlength to the width of the sheets and communicating with the spacebetween the sheets. At least a portion of end wall 100 is formed of aflexible material such as rubber which may be pierced by the hollowneedle 104 of a syringe through which a quantity of processing fluid maybe introduced into chamber 102 for spreading between the sheets. Thisform of film unit may be employed in a camera of the type shown in FIG.4 and described above, the rear section of the camera being sufficientlyenlarged to include the components of a syringe having a hollow needle104 which extends into upper enlarged end sections 60 of passage 58 inposition to pierce wall 100 of retaining ele ment 94 as the film unit ismoved into exposure position. When the film unit is in exposureposition, the open end of needle 104 is located within chamber 102 andthe syringe, the construction and operation of which will be describedhereinafter, may be actuated to inject a predetermined quantity ofprocessing fluid into said chamber.

Another embodiment of a film unit of the type wherein the processingfluid is injected into a chamber communicating with the space betweenthe sheets by a syringe is illustrated at 106 in FIG. 8 of the drawings.Film unit 106 comprises a pair of rigid sheets 108 and 110 securedtogether in facing relation at their lateral margins preferably by anadhesive which obviates the necessity for separate retaining elements.Sheet 110 may include a flange 112 along one end edge adapted to extendacross the space between the sheets toward the outer surface of sheet108 beyond the end of the latter to aid in positioning the sheetsrelative to one another and/ or prevent the admission of light betweenthe sheets. There is provided secured around the opposite ends of thesheets an enclosure element 114 secured, for example, by an adhesive anddefining a chamber 116 extending at least from side to side of thesheets and communicating with the space between the sheets. Film unit106 is employed in substantially the same manner as film unit 94,enclosure element 114 having an end wall adapted to be pierced by theneedle of a syringe.

The aforementioned syringe, adapted to be embodied in a camera 48 andemployed in conjunction with film units of the type described, isillustrated in FIG. 9 of the drawings and designated at 118. The syringeincludes a cylindrical barrel 120 closed at one end by a plug or cap 122having an opening through which extends a shaft 124 attached to aplunger or piston 126 located for sliding movement within barrel 120. Acap 128 is provided on the opposite end of the barrel 120 and includes atapered neck 130 at the end of which is secured needle 104. Neck 130 iscurved, depending on the location and position of the syringe within thecamera relative to enlarged end section 60 of slot 56 so that needle 104extends into section 60 in position to pierce the end wall of theelement of the film unit introduced into section 60. Barrel 120 ispreferably adapted to contain, when piston 126 is located against plug122, processing fluid in an amount suflicient for a plurality of filmunits and means are provided for moving piston 126 sufficiently a numberof times so that during each movement an amount of fluid sufficient toprocess one film unit is ejected through needle 104. This means formoving plunger 126 and controlling the amount of fluid ejected therebyincludes an actuating bar 132 having formed along one side thereof aseries of projecting teeth 134 positioned in engagement with anengagement member 136 secured to the end of shaft 124. Each of teeth 134includes a flat projecting face adapted to positively engage member 136when operating bar 132 is moved in one direction (upward viewing FIG. 9)so as to move shaft 124 and piston 126 axially (upward) away from plug122 toward cap 128 and thereby cause the ejection of fluid contained inbarrel 120; and an inclined face which coacts with engagement member 136to deflect to the latter rather than engage member 136 when operatingbar 1 32 is moved (downward) in the opposite direction. So thatengagement member 136 may be deflected during downward movement of bar132, member 136 is provided with a slot 138 through which shaft 124projects. The shaft includes locking rings 140 located on opposite sidesof member 136 so as to prevent axial movement of the shaft wit-h respectto member 136 while permitting movement of the member in a planeperpendicular to the axis of said shaft. Resilient means, such as a leafspring 142, is provided in engagement with member 136 for urging themember into engagement with teeth 134 on operating bar 132. The distancebetween the flat faces of adjacent teeth is substantially equal to thelength of the upward movement of piston 126 necessary to eject the predetermined amount of fluid required for processing one film unit.Operating bar 132 is so mounted as to be slidable in the direction ofits elongation, movement of bar 132 being limited to this same distancebetween flat faces of adjacent teeth so that one movement (upward) ofthe bar can cause theejection of only suflicient fluid to process onefilm unit. A spring, indicated at 144, may be provided for urgingoperating bar 132 upward to the full limit of its movement in thedirection required to cause the ejection of fluid and bar 132 isprovided with an engagement arm 146 which projects exteriorly of thecamera housing, for example through a slot therein, to provide means formanually operating the syringe. Engagement member 136 also includes amanually engageable arm 148 adapted to project exteriorly of the camerahousing.

The syringe is operated to inject a predetermined quantity of processingfluid into a film unit in response to arm 146 being manually depressedso as to move bar 132 downward against the bias of spring 144 to itslimit of movement, at which point the flat face of one of teeth 134engages member 136 and then moving bar 132 and/ or allowing the bar tomove under the bias of spring 144 upward to the limit of its movement,thereby causing a quantity of fluid to be ejected from the syringe. Thisreciprocating movement is imparted to operating bar 132 for eachsuccessive film unit to be processed, member 136 being deflected fromengagement with teeth 1'34 during downward movement and being engaged bythe next successive tooth 134 on the upward movement of bar 132. Thebarrel of the syringe can be refilled by inserting a container, filledwith the processing fluid and having a flexible end closure, into upperenlarged section 6%) of passage 56 until needle 1M punctures the endclosure. Piston 126 is then drawn downward toward plug 122, causing thefluid to be drawn from the container into barrel 120. To permit downwardmovement of the piston, engagement arm 1 .8 is manually grasped and ismoved against the bias of spring 142 from engagement with teeth 134.Engagement member 136 may then be moved downward to a position whereinmember 136 will be engaged by the flat face of the first or lowest tooth134 when bar 132 is again depressed.

Reference is now made to FIGS. and 11 of the drawings wherein there isshown another form of film unit designated at 150 and embodying theinvention together with means formanipulating the film unit to cause thespreading of the processing fluid between the sheets. Film unit 150includes, in addition to a pair of rigid sheets 152 and 154 securedtogether in facing relation with their inner surfaces spaced apredetermined distance apart, a collapsible container 156. Container 156is formed preferably of a single rectangular sheet of flexible material,such as paper, plastic, metallic foil and the like, which is imperviousto the processing fluid and preferaby water vapor impervious. Thissheet, at least as long as the width of sheets 152 and 154, is foldedupon itself and its longitudinal edge sections 158 (opposite the fold)are secured to the ends of sheets 152 and 154. The end edges of thesheet are bonded together to define a cavity communicating with thespace between the sheets. This cavity is divided longitudinally into twosections by bonding or adhering the inner surfaces of the sides of thecavity together along a region, indicated at 160 and located mediate thefold and edge sections 158. The film unit is provided with cavity 162located nearest the fold containing a quantity of fluid 164 suflrcientto at least completely fill the space between the sheets when spreadtherebetween, while the second cavity 166, which communicates directlywith the space between the sheets, is empty. To release the fluid withincavity 166 for spreading between the sheets, the Walls of container 156in the region of fluid-filled cavity 162 are subjected to compressivepressure, for example, by such means as a pair of jaws 168. The pressurethus generated in fluid 164 causes the bond between the walls of thecontainer in region 166 separating the two cavities from one another torupture and the fluid to flow into cavity 166 so that it can be drawninto the space between sheets 152 and 154 by capillary action. Jaws 168may be very simple in construction and operation and may be provided inthe camera; or, if it is desired, under certain circumstances thecontainer may even be compressed manually prior to introduction of thefilm unit into the camera.

While various forms of film units have been shown and described,including specific means for supplying a quantity of processing fluidand releasing said fluid in a chamber associated with the end of a pairof sheets,

spaced apart so that said fluid is caused to be spread therebetween bycapillary action, and communicating with the space between the sheets,other forms of film units falling within the scope of the invention mayoccur to persons skilled in the art. For example, the processing fluidmay be provided in a frangible container mounted within a flexibleenclosure providing a chamber communicating with the space between thesheets. The frangible container, which provides a barrier between thefluid and the space between the sheets, may be adapted to be crushed orbroken by compressive pressure applied through the walls of theenclosure so as to re lease its contents for spreading between thesheets. A frangible container suitable for use in the present inventionis disclosed in my Letters Patent No. 2,627,459, issued February 3,1953.

Since certain changes may be made in the above product and processwithout departing from the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

What is claimed is:

l. The method of treating a light-sensitive material located in a layerbetween a pair of liquid-confining sheets to form a visible photographicimage, which method comprises the steps of: forming a capillaryinterspace of substantially uniform capillary depth throughout itslength and width between the inner surfaces of said sheets bysuper-posing said sheets with said inner surfaces spaced a predeterminedminute distance apart and so holding said sheets with said innersurfaces thereof rigidly fixed with respect to one another that afree-flowing liquid will move through said capillary interspace bycapillary action to form a continuous layer of substantially uniformthickness throughout the length and width of said. interspace; supplyinga quantity of a free-flowing liquid, including an agent capable ofinitiating the processing of said light-sensitive material to produce avisible image, to said interspace between said sheets at one edgethereof; spreading said liquid in a layer between said sheets bycapillary action to form a sandwich including saidlight-sensitivematerial and said agent for initiating processing; atsome stage in said method, exposing said light-sensitive material toactinic radiation to produce an image in said light-sensitive material;and reacting said liquid with said exposed light-sensitive material toproduce a visible photographic image.

2. The method of claim 1 wherein said liquid is spread prior to exposureof said light-sensitive material to actinic radiation.

3. The method of treating a light-sensitive material located between apair of substantially liquid impervious rigid sheets to form a visiblephotographic image, which method comprises forming a capillaryinterspace of substantially uniform capillary depth throughout itslength and width between the inner surfaces of said sheets bysuperposing said sheets with said inner surfaces fixedly spaced from oneanother by a minute distance such that a free-flowing liquid will movebetween said sheets by capillary action to form a sandwich including auniformly distributed photosensitive material; supplying a quantity of afree-flowing aqueous liquid reagent capable of processing an exposedlight-sensitive material to produce I a visible image, to said capillaryinterspace between said sheets at one edge thereof; spreading saidliquid reagent in a thin layer of substantially uniform thicknessthroughout the length and width of said interspace between said sheetsby capillary action to form a sandwich including a continuous layer ofsaid liquid and said uniformly distributed photosensitive material;exposing said photosensitive material to produce an image therein; andreact ing said liquid reagent with said exposed photosensitive materialto form a visible photographic image.

4. The method of claim 3 wherein said quantity of said free-flowingliquid is provided initially in a chamber communicating with saidinterspace at said one edge, flow of said liquid from said chamber intosaid capillary interspace is prevented by a barrier provided in saidchamber, and said barrier is withdrawn from said chamher for releasingsaid liquid to flow into said capillary interspace for spreading withinsaid interspace by capillary action.

5. A photographic method as defined in claim 3 wherein said free-flowingliquid reagent is supplied to said interspace from a chambercommunicating with said capillary interspace at said one edge, saidchamber is defined by a container located externally of said sheets andcoupled with said one edge of said sheets, a wall of said container isperforated by forcing a tubular member through said wall into saidchamber and a quantity of said liquid reagent is introduced through saidtubular member into said chamber to be withdrawn therefrom into saidcapillary interspace between said sheets by capillary action.

6. A photographic method as defined in claim 3 wherein said quantity ofsaid free-flowing liquid reagent is provided in a first section of a twosectioned container located externally of said sheets and having asecond sec-, tion providing a chamber coupled with said sheets at oneedge thereof and communicating with said interspace between said sheets,and compressive pressure is applied to said first section of saidcontainer for causing its liquid contents to be discharged into saidchamber of said second section to be withdrawn therefrom into saidinterspace between said sheets by capillary action.

7. A photographic method as defined in claim 3 comprising providing saidquantity of said free-flowing liquid in an elongated container locatedwithin a chamber disposed externally of said sheets and communicatingwith said capillary interspace at said one edge of said sheets,withdrawing said container in the direction of its elongation from saidchamber and as said container is being withdrawn, causing said liquid tobe discharged from said container into said chamber to be withdrawn bycapillary action into said capillary interspace between said sheets.

8. A photographic product in the form of a film unit comprising a pairof substantially rigid, liquid-confining sheets superposed with theirinner surfaces in substantially fixed relation and rigidly spaced apredetermined minute distance apart to provide a continuous capillaryinterspace of substantially uniform capillary depth between said sheetsthrough which a free-flowing liquid will move by capillary action toform a continuous layer for effecting the processing of a layer ofphotographic, photosensitive ima'ge-recording material located betweenthe outer surfaces of said sheets; a layer of a photographic materialdisposed between said sheets on one of said sheets, said sheets havingat least a pair of adjacent edges defining a boundary of saidinterspace; means located externally of said sheets and secured to atleast one of said sheets adjacent said edges for containing a quantityof said liquid; means for conducting said liquid to said interspacebetween said sheets at said adjacent edges so that said liquid may bedrawn by capillary action into said interspace between said sheets; andmeans for releasing said liquid to flow into said interspace, saidphotosensitive material being provided initially in one of said layerbetween said sheets and said liquid.

9. A photographic product in the form of a film unit comprising a pairof substantially rigid, liquid-impervious sheets fixedly supported insuperposed relation with their inner surfaces spaced a predetermineddistance apart to provide a continuous capillary interspace ofsubstantially uniform depth between said sheets within which afree-flowing liquid will move by capillary action; photographic,photosensitive image-recording material; a developer for saidphotosensitive material capable of reacting therewith to product avisible image; a layer of a photographic material disposed between saidsheets on one of said sheets, a quantity of a free-flowing aqueousliquid capable of initiating the development of said photosensitivematerial following exposure thereof; each of said sheets having an edgesubstantially adjacent said edge of the other of said sheets; saidinterspace extending to said adjacent edges; means located externally ofsaid sheets and coupled with said sheets at said edges providing achamber communicating with said interspace at said edges for containingsaid quantity of said liquid and for conducting said liquid to saidinterspace so that said liquid may be drawn by capillary action intosaid interspace between said sheets; and means releasably re tainingsaid liquid in said chamber apart from said interspace, saidphotosensitive material and said developer therefor being providedinitially in at least one of said layer between said sheets and saidliquid.

10. The photographic product of claim 9 wherein said means forcontaining and conducting said liquid to said space between the sheetscomprises a collapsible container located externally of said sheets andincluding a first section providing said chamber for containing saidliquid and a second section communicating with said capillaryinterspace, the Walls of said second section of said container beingsecured to the exterior marginal portion of said sheets at said edges,said first and second sections of said container being separated by asealed portion capable of being ruptured by the application ofcompressive pressure to said first section of said container to permitthe flow of said liquid from said first section into said second sectionwhere said liquid is available to be drawn into said capillaryinterspace.

11. A photographic product in the form of a film unit comprising a pairof substantially rigid, liquid-impervious sheets fixedly supported insuperposed relation with their inner surfaces spaced a predetermineddistance apart to provide a continuous capillary interspace ofsubstantially uniform depth between said sheets within which afreeflowing liquid will move by capillary action; photographic,photosensitive image-recording material; a developer for saidphotosensz' ve material capable of reacting therewith to produce avisible image; a quantity of a free-flowing aqueous liquid includingsaid photosensitive material and at least one ingredient of saiddeveloping composition for said photosensitive material, the remainingingredients of said developing composition being disposed on one of saidsheets between sheets and so constituted to be rendered reactive bycontact with said liquid; each of said sheets having an edgesubstantially adjacent said edge of the other of said sheets; said spaceextending to said adjacent edges; means located externally of saidsheets and coupled with said sheets at said edges providing a chambercommunicating with said interspace at said edges for containing saidquantity of said liquid and for conducting said liquid to saidinterspace so that said liquid may be drawn by capillary action intosaid interspace between said sheets; and means releasably retaining saidliquid in said chamber apart from said interspace.

12. A photographic product in the form of a film unit comprising a pairof substantially rigid liquid-impervious sheets located in superposedrelation; holding means fixedly retaining said sheets with their innersurfaces rigidly spaced a predetermined fixed distance apart to providea continuous capillary interspace of substantially uniform capillarydepth between said inner surfaces through which a free-flowingphotographic liquid will move between said sheets by capillary action toform a sandwich comprising at least three layers, at least one of saidlayers being located between the outer surfaces of said sheets,comprising said liquid, being continuous and including a uniformlydistributed photographic, photosensitive image recording material; saidsheets having adjacent edges defining one end of said interspace; acontainer located externally of said sheets and secured to said sheetsat said adjacent edges; said container providing an elongated chamberextending approximately from side to side of said interspace at saidadjacent edges and carrying a quantity of said free-flowing photographicliquid for distribution within said interspace; means for conductingsaid liquid from said chamber to said interspace at said adjacent edges;and an elongated barrier within said container means for preventing theflow of said liquid from, said chamber into said interspace, said 14barrier means being movable from said chamber in the direction ofelongation of said barrier substantially parallel with saidadjacentedges of said sheet to permit the flow of said liquid to said interspacefor distribution throughout said interspace by capillary action.

13. The photographic product of claim 12 wherein said liquid comprisessaid photosensitive material and at least one ingredient of a developingcomposition for said photosensitive material, and the remainingingredients of said developing composition are deposited between saidsheets on one of said sheets in condition to be rendered reactive bycontact with said liquid.

14. The photographic product of claim 12 wherein said container alsoprovides a passage connecting said chamber with said capillaryinterspace at said adjacent edges, and said barrier comprises a memberlocated in closing relation in said passage between said chamber andsaid interspace.

15. The photographic product of claim 12 wherein said barrier comprisesan elongated tubular member containing said liquid; and means areprovided for engaging said tubular member during withdrawal thereof fromsaid chamber in the direction of elongation of said tubular member toeffect the release of said liquid in said chamber for distributionwithin said interspace.

16. The photographic product of claim 15 wherein said means engagingsaid tubular member to release said liquid comprise means forprogressively compressing the walls of said tubular member duringwithdrawal thereof to cause the discharge of said liquid from saidtubular member into said chamber.

References Cited in the file of this patent UNITED STATES PATENTS1,678,218 Gruss July 24, 1928 2,501,418 Snowden Mar. 21, 1950 2,659,825Land Nov. 17, 1953 STATE s PATENT" OFFICE CERTIFICATE OF CORRECTIONPatent N00 3 O69 266 December 18,I 1962 Edwin H, Land It is herebyceriified that error appears in the above numberedpaten't'requiring;oorrection'and that the said Letters Patent shouldread as corrected below."

Column 1 lines 29 and 30,, for "received" read receives column 2, line63 for "benig read being column 3 line 27 for "May 21, 1961" read May- 21961 column 7, line 56, for "Fuid" read Fluid column 9 line 3 strike out"to", second occurrence; column 12 line 3O for "product" read produceSigned and sealed this 15th day of December 1964 SEAL At t esiz ,SWlDER'EDWARD J BRENNER Attesti ng" Officer Commissioner of Patents

1. THE METHOD OF TREATING A LIGHT-SENSITIVE MATERIAL LOCATED IN A LAYERBETWEEN A PAIR OF LIQUID-CONFINING SHEETS TO FORM A VISIBLE PHOTOGRAPHICIMAGE, WHICH METHOD COMPRISES THE STEPS OF; FORMING A CAPILLAYRINTERSPACE OF SUBSTANTIALLY UNIFORM CAPILLARY DEPTH THROUGHOUT ITSLENGTH AND WIDTH BETWEEN THE INNER SURFACES OF SAID SHEETS BYSUPERPOSING SAID SHEETS WITH SAID INNER SURFACES SPACED A PREDETERMINEDMINUTE DISTANCE APART AND SO HOLDING SAID SHEETS WITH SAID INNERSURFACES THEREOF RIGIDLY FIXED WITH RESPECT TO ONE ANOTHER THAT AFREE-FLOWING LIQUID WILL MOVE THROUGH SAID CAPILLARY INTERSPACE BYCAPILLARY ACTION TO FORM A CONTINUOUS LAYER OF SUBSTANTIALLY UNIFORMTHICKNESS THROUGHOUT THE LENGTH AND WIDTH OF SAID INTERSPACE; SUPPLYINGA QUANTITY OF A FREE-FLOWING LIQUID, INCLUDING AN AGENT CAPABLE OFINITIATING THE PROCESSING OF SAID LIGHT-SENSITIVE MATERIAL TO PRODUCE AVISIBLE IMAGE, TO SAID INTERSPACE BETWEEN SAID SHEETS AT ONE EDGETHEREOF; SPREADING SAID LIQUID IN A LAYER BETWEEN SAID SHEETS BYCAPILLARY ACTION TO FORM A SANDWICH INCLUDING SAID LIGHT-SENSITIVEMATERIAL AND SAID AGENT FOR INITIATING PROCESSING; AT SOME STAGE IN SAIDMETHOD, EXPOSING SAID LIGHT-SENSITIVE MATERIAL TO ACTINIC RADIATION TOPRODUCE AN IMAGE IN SAID LIGHT-SENSITIVE MATERIAL; AND REACTING SAIDLIQUID WITH SAID EXPOSED LIGHT-SENSITIVE MATERIAL TO PRODUCE A VISIBLEPHOTOGRAPHIC IMAGE.